GMAT Practice Questions - Paradox - August 03, 2013

A doctor begins a skin cancer patient on a new treatment that has met with great success in other patients. The new treatment involves a new drug and is less painful and invasive than some of the other available options and is more advanced and specialized. However, after she begins the new treatment, the patient's health begins to decline.

Which of the following, if true, would give the best partial explanation of the discrepancy above?

(A)While this drug does kill these cancer cells, this is
just one application for which it is commonly prescribed.

(B)The drug is not particularly discerning between cancer
and non-cancer cells.

(C)The patient began other treatments right after she
started taking the drug.

(D)Right after beginning the drug, the patient recovered
from a case of pneumonia.

(E)Of all the cancer drugs on the market, the prescribed
drug has the highest success rate.